Sliding door operator

ABSTRACT

A sliding door operator incorporating a rotating shaft and means on the door to be moved including opposing rollers engaging the shaft with their axes parallel to the shaft when the door is stationary and with their axes displaced from their parallel position in either direction to effect a helical engagement of the rollers on the shaft for door movement in either direction.

United States Patent 1 June 20, 1972 Primary Examiner-J. Karl Bell Attorney-Gradolph, Love, Rogers & Van Sciver [57] ABSTRACT A sliding door operator incorporating a rotating shaft and means on the door to be moved including opposing rollers engaging the shaft with their axes parallel to the shaft when the door is stationary and with their axes displaced from their parallel position in either direction to effect a helical engagement of the rollers on the shaft for door movement in either direction.

19 Claims, 20 Drawing Figures SLIDING DOOR OPERATOR BACKGROUND OF THE INVENTION 1. Field of the Invention This invention relates to remotely actuated sliding doors as by a mat switch or an electric eye.

2. Description of the Prior Art The powered operation of sliding doors for the most part has been by the use of hydraulic motors or a screw thread. Hydraulic operation is unsatisfactory because of the high variation of rates of closing or opening with variations in ambient temperature. Screw thread operation has the disadvantage of being too positive. If a person or a grocery cart should be caught in a closing door, provision must be made for an easy breakaway of the mechanism connecting the door to the drive or for an interruption of the drive itself, both of which would disable the apparatus until the necessary resetting could be achieved. It possesses the further disadvantage that the door moves to its fully open or fully closed position at the same rate of speed at which it travels in the central part of its movement. Thus, the velocity of movement of the door must be a compromise between getting the door closed as fast as possible, while at the same time having not too great a deceleration at the instant of full closure.

SUMMARY OF THE INVENTION This invention teaches a shaft powered for rotation in one direction only. The door to be operated carries a yoke surrounding the shaft which contains rollers bearing oppositely against the shaft. The rollers are mounted within the yoke to have their axes parallel to the shaft when the door is motionless, but the yoke permits a rotation of the axial support of the rollers about a line normal to the surface of the shaft such that the rollers may be turned to engage the surface of the shaft helically. This rotation is possible in both directions, and thus the rotation of the shaft in its single direction may move the yoke in either direction thereon depending on the angular position of the roller axes. The engagement of the rollers on the shaft is frictional such that a jamming of the door will slip the rollers on the shaft, and the rate of traverse of the door may be adjusted by the angular displacement of the axes of the rollers from the parallel relationship with the shaft.

Attention is directed to U.S. Pat. Nos. 3,473,393 to Zaruba and 3,475,972 to Steibel as showing the general mechanism on which this invention is premised.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an elevation of a sliding door assembly with a covering panel broken away to show the door operating mechanism;

FIG. 2 is an enlarged section of the upper left-hand part of FIG. 1 illustrating the hinged connection of the door to the carrying trolley;

FIG. 3 is a section taken along the line 3-3 of FIG. 2 looking in the direction of the arrows;

FIG. 4 is an end elevation of the operating mechanism taken along the line 4-4 of FIG. 1 looking in the direction of the arrows;

FIG. 5 is a front elevation of the operating mechanism taken from the line 5-5 of FIG. 4 looking in the direction of the arrows;

FIG. 6 is a section taken along the line 6-6 of FIG. 5 showing the roller controllers partially in section and partially in elevation in a neutral relationship;

FIG. 7 is a view similar to FIG. 6 showing, however, the parts thereof in the course of door movement;

FIG. 8 is again similar to FIG. 6, but showing the parts at the end of the movement of FIG. 7;

FIG. 9 is a section taken along the line 9-9 of FIG. 6;

FIG. 10 is a section taken along the line 10-10 of FIG. 7;

FIG. 11 is a view similar to FIG. 5 showing, however, optional mechanism for reversing door travel;

FIG. 12 is a view taken along the line 12-12 ofFlG. 11;

FIG. 13 is a view somewhat similar to FIGS. 5 and 11 showing, however, another optional mechanism for reversing door travel;

FIG. 14 is a view taken along the line 14-14 of FIG. 13 looking in the direction of the arrows;

FIG. 15 is a view taken along the line 15-15 of FIG. 13 looking in the direction of the arrows;

FIG. 16 is a somewhat diagrammatic view of the arrangement of cams and cam roller positions whereby the door travel is controlled;

FIG. 17 is a circuit diagram applicable to the device of FIGS. 1 through 10;

FIG. 18 is a central longitudinal section analogous to FIG. 9 illustrating an optional servo and roller yoke assembly;

FIG. 19 is a section through the structure of FIG. 18 viewed from the line 19-19 of that figure; and

FIG. 20 is a top plan view of the left end portion of FIG. 18.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1 is shown a door opening 10in which the device of this invention is to be employed. A top frame member 12 surmounts the door opening and contains and supports the door or doors and operating structure. The frame member is a rectangular tube in cross-section with a slot 14 in the bottom thereof. As usually supplied, the unit will include a pair of glass doors, one of which is stationary and the other of which is movable to open and close that portion of the doorway left uncovered by the stationary door. It will be appreciated, however, that the movable door only may be furnished, and, of course, the material of the door is irrelevant as far as this invention is concerned. The movable door 16 alone is shown.

The front face 18 of the frame member is shown removed in FIG. 1 to illustrate the operating contents thereof. The support member includes a longitudinal track 20 along the back wall 22 thereof, and the door 16 is carried by a trolley 24 with 7 wheels 25 at each end thereof which ride on the rail 20. A

cylindrical shaft 26 is journaled for rotation in brackets 28 extending downwardly from the top wall 30 of the support member 12. The shaft is driven through a V-belt coupling 32 by a motor 34 mounted at one end within the support member 12. The V-belt drive permits an advantageous positioning of theshaft 26. A pair of longitudinally spaced earns 36 and 38 likewise extend downwardly from the top wall of the support member.

The trolley 24 is best illustrated in FIG. 4. It is essentially an elongated member, L-shaped in cross section, with an upstanding vertical web 40 adjacent the back wall 22 of the support member and a horizontal web 44 extending to the front from the lower edge of the vertical web 40. The vertical web has the wheels 25 secured thereto as by stub shafts 46. The horizontal web 44 includes provision on its bottom surface over the slot 14 for mounting the door 16. Its top surface 50 constitutes a table to which various elements of the actuator assembly 52 are mounted.

Although the door 16 is primarily intended for a sliding opening under the power of the operating mechanism, it is desirable that the door also be capable of being opened pivotally to meet emergency situations such as power failure or fire. Accordingly, the door is mounted in the fashion illustrated in FIGS. 2 and 3. In FIG. 3 it will be noted that the horizontal web 44 of the trolley has a pair of spaced flanges 54 and 56 extending downwardly therefrom, the inner 56 of which is longer and constitutes a door stop. The horizontal web 44 has a large diameter hole 58 formed therein on the axis of pivoting of the door and a hole 60 of smaller diameter spaced therefrom along the horizontal web in the direction of the free edge of the door 16. A rectangular pivot plate 62 having an outer end 63 of somewhat reduced thickness lies between the two flanges 54 and 56 under the two holes 58 and 60.

The pivot plate has a bore 64 vertically therefrom concentric with the hole 58 but appreciably smaller than that hole. It

also has a tapped hole 66 in the outer end 63 underlying the hole 60 in the horizontal web 44. The pivot plate is secured between the flanges 54 and 56 by a pair of stub shafts 67 extending through appropriate horizontal bores in the two flanges and aligned horizontal bores in the pivot plate. Likewise, a headed bolt 68 is extended down through the hole 60 to engage the threads of the tapped hole 64. Thus, the pivoted plate can rock on the stub shafts 66 to the limited degree permitted by the adjustments of the bolt 68.

A door arm support 70 is secured by appropriate throughfastenings 72 to support the swinging door panel 74 proper. The door arm support possesses a relatively large diameter, threaded stud 76 extending up through the hole 64 in the pivot plate, and a nut 78 threaded on the upper end of the stud 76 holds the door arm support to the pivot plate. It will be appreciated that this support is the sole support of the door. Since the weight of the door is otherwise unsupported and grossly uncentered with respect to its sole support, the pivot plate provides compensan'on for such tendency the door may have to sag.

Any appropriate latch or detent may cooperate between the door and the trolley 24, for instance, to hold the door in its closed, sliding position in breakaway fashion. As such expedients are well known, it has not been illustrated.

Referring particularly to FIGS. 4, 5, 9 and 10, the actuator assembly 52 makes direct door driving connection with the shaft 26 by means of a roller assembly 80. The roller assembly consists of a housing 82 surrounding the shaft 26 and having three tubular projections or lobes 84 extending radially outward and spaced equally at 120 from each other. The central apertures 86 of the lobes contain a pair of sleeve bearings 88 extending substantially the length of the apertures, and inside these bearings, a cylindrical roller block 90 is contained. The roller block has a transverse slot 92 therein extending from end to end and nearly spanning the block, and a bore 94 intersecting the slot 92 extending radially across the block. A roller 96 equipped with bearings 98 is contained within the slot 92 and a wrist pin 100 is contained within the bore 94 and constitutes a shaft for the roller 96. The periphery of the roller 96 as thussupported by the pin 100 extends beyond the roller block at its inner end as at 102.

The lobes 84 have threaded bores 104 therein oriented parallel with the shaft 26 through which the wrist pins 100 may be inserted for assembly (the sleeve bearings88 being likewise apertured) and into which mounting studs 106 are afterwards screwed. The mounting studs mount the roller housing 80 to an L-shaped bracket 108 (FIG. 5) with rubber washers 109 interposed which, in turn, is secured to the top of the horizontal web 44 of the trolley 24. The rubber washers 109 provide a resilience of mounting whereby the roller assembly is self-centering on the shaft 26, the desireability of which will appear in the course of further description.

The wrist pin 100 terminates at that end adjacent the bore 104 within the confines of the roller block 90. At its other end, the pin extends beyond the confines of the roller block and terminates exteriorly of the lobe 84 in a neck 1 10 of reduced diameter and a rounded head 112. The extension of the head and neck of the pin is through a slot 113 in the sleeve bearings 88 and the wall of the lobe 84 oriented circumferentially of the lobe.

The roller blocks 90 have a central recess 114 in their outer ends which contain a needle thrust bearing 116 and a cupped disk washer 118 standing outwardly of the roller blocks. The lobes 84 are interiorly threaded at their outer ends to receive a bearing cap 120. Thus, the rollers 96 are mounted to bear forcibly but resiliently against the shaft 26, in center position, with the axes of the rollers parallel to the axis of the shaft. The roller blocks 90, however, are permitted a limited degree of rotation to either side of the center position by virtue of the containment of the headed end 112 of the wrist pin 100 in the slot 113. Such rotation throws the axial relationship of the shaft and rollers out of parallel and produces a helical bearing of the rollers on the shaft. The pitch of the helical engagement is continuously variable from none to relatively great in either direction depending on the degree of rotation of the roller blocks.

The roller housing 82 includes a sleeve 120 encompassing the shaft extending from the lobed portion on the same side thereof as the protruding wrist pin heads 112. The sleeve is grooved at its outer end for the reception of a retaining ring 122.

The roller housing 82 also possesses an integral upstanding car 121 between the two upper lobes with a horizontal bore therein into which is press-fitted a pin 123 extending horizontally out parallel to shaft 26 into the same general vertical plane as the heads 1 12 of the wrist pins 100.

The retaining ring 122 retains on the sleeve 120 two independently rotatable members, a roller yoke 124 and a servo yoke 126. The roller yoke is a molded shallow cylindrical body with recesses or pockets in that face opposing the roller housing 82, a pair of outstanding lugs 128 on the opposite face, and an integral boss 130 projecting vertically upward from the periphery thereof when the door is in normal or unmoving condition, or the rollers 96 are directly transverse to the shaft 26.

Of the pockets referred to above, three are wrist pin head pockets 132 spaced 120 apart on the indicated face of the roller yoke on a circle concentric with shaft 26 to receive the pin heads 112 therein. The pockets are long to accommodate the arcuate movement of the pockets to the linear movement of the heads, but are narrow to confine the heads laterally closely. It will be thus appreciated that rotation of the roller yoke 124 on the sleeve 120 of the roller housing 82 will rotate the roller blocks, all to a like degree, and thus produce or change the helical engagement of the rollers 96 on the shaft 26.

The roller yoke has a fourth pocket 134 on the same face which is located within the boss 130. A pair of speed control screws 136 are threaded into opposite sides of the boss to enter the ends of the pocket to an adjustable degree. The pocket 134 receives the speed control pin 123 of the roller housing 82 as best seen in FIG. 9 and in dotted lines in FIGS. 6, 7, and 8, and meets the screws at the end points of arcuate travel of the roller yoke. The speed control screws limit the arcuate movement of the roller yoke and thus the maximum pitch of the helical engagement of the rollers 96 on the shaft 26 to put a limit to the speed of door traverse. Since the screws independently establish limits on either side of the transverse roller position, the speed of door opening may be adjusted to be considerably greater than the speed of door closing, as is usually desired.

The boss 130 mounts a cam follower roller 138 on its top surface by means of a vertical stub shaft 140. The cam follower is thus positioned to intercept the cams 36 and 38 mounted to the top wall 30 of the support member 12.

The lugs 128 on the opposite side of the roller yoke 124 are narrow, elongated, integral projections equally and oppositely spaced from the center of the yoke and with a slight curvature to constitute segment of a circle.

The servo yoke 126 is also a generally shallow cylindrical molding with an integral projection or servo arm 142 extending from the periphery upward and to the front. In that face which opposes the roller yoke, a slightly-less-than-semicircular, relatively wide groove 144 is formed to be concentric with the sleeve 120 (FIGS. 6, 7 and 8). The groove has narrow extensions 146 at each end, substantially longer than the lugs 128 of the roller yoke and following the same curvature to bring the total length of groove 144 plus extensions to more than Shoulders 147 mark the transition between the groove 144 and the extensions 146. The lugs 128 are accommodated within the groove extensions 146. A coil spring 148 under compression is lodged in the groove proper, seating in a centered position against the shoulders 147. The centered position of the roller assembly 80 will be as illustrated in FIG. 6, with the lugs 128 entirely contained in the groove extensions 146 but flush with the shoulders 147, leaving the ends of the extensions empty and available for lug retraction into them.

A servo assembly 150 completes the actuator assembly 52. The servo assembly constitutes a link between the trolley and the servo arm 142 and operates to rock the servo yoke 126 one way or the other. To this end, a plate 152 bearing a pair of spaced ears 154 is mounted to front edge 156 of the horizontal web 44 of the trolley 24 and an arm 158 welded to the gear housing 160 of a servo motor 162 is pivoted between the ears 154 by a pin 164. The servo motor 162 is reversible.

Within the gear housing, a worm 166 is mounted to the shaft of the servo motor to drive a pinion (not shown) mounted on the lower end of a threaded shaft or screw 168. The screw 168 is in a generally rectangular closed housing 170 integral with the gear housing 160 and extending upward therefrom. One side 172 of the housing 170 is positioned flat against the servo arm 142.

A nut 174 is threaded on screw 168. The nut has a rectangular post 176 extending laterally therefrom through a slot 178 in the housing wall 172 to the servo arm 142. The alot is parallel to screw 168. A cap screw 180 extends through the servo arm and is threaded into the end of post 176 to link the servo arm to the nut 174. The nut thus is held against rotation.

On the wall 182 opposite the wall 172 of the housing a reversing switch actuator 184 is located. This actuator is a U- shaped member having legs 186 extending through slots 188 in the wall 182 into the interior of the housing. The central portion 190 of the actuator is contained against the outside surface of the wall 182 between the clots 188 by the screws 192 extending through longitudinal slots 194 in the central portion 190 of the actuator. The actuator has a block- 196 extending from the back outer surface thereof, and a microswitch 198 with an arm 200 is positioned to be actuated by movement of the block 196. As will be described later, the microswitch is a part of the servo reversing circuitry.

FIG. 16 is a view looking up at the top wall 30 of the support member 12 showing the fixed limit cams 36 and 38 which determine the end point of door travel. The cams are identical and consist of a length of angle iron secured along one web by a pair of screws 202 to the top wall 30 of the support member 12. It is desirable that one of the screws occupy a transverse slot 204 at one end of the cams for adjustment of the door travel. The other webs 206 extend vertically downward. The cams are positioned to be at a sharp angle with respect to door travel and generally parallel to each other. The cams coact with the cam follower roller 138, and thus are positioned in the line of movement of the cam follower.

The electrical circuit for the device thus far described is illustrated in FIG. 17.

The motor 34 and a normally open, relay switch 220 are connected across a source 222 of a 115 v. current to constitute a door opening circuit 221. A door closing circuit 223 extends in parallel with switch 220, also to engage motor 34, and includes normally open, relay switch 225. The primary 224 of a 24 volt transformer 226 is connected in parallel with the circuit 221 also across the source of power.

A normally open, door opening mat switch 228 (not elsewhere shown) and the solenoid 230 of a mat relay 231 are connected across the secondary 232 of the transformer 226 in a first or mat circuit 234. A second, safety mat switch 236, (also not elsewhere shown, but to be located on the remote or departure side of the door), and the solenoid 238 of a safety relay 239 are also connected across the secondary 232 in a safety circuit 240. This circuit is to prevent the door closing when a person is lingering in the doorway.

A third, time delay circuit 242 is also connected across the secondary. This circuit contains a normally closed switch 244 of the mat relay 231, a normally closed switch 246 of the safety relay 231, a normally open switch 248 actuated by the solenoid 250 of a holding relay 251, and the thermal element 252 of a time delay relay 253.

The time delay relay 253, shown, of course, in unenergized condition, is a thermal type wherein the contacts are moved as by a bimetallic element to their energized position a measured period of time after energization of the thermal element (2 seconds is conventional in door operating apparatus) and are restored to starting position a further predetermined period after de-energization of the thermal element 252. The delay relay includes switch 225 connected to energize the motor 34.

The solenoid 250 of the holding relay 251 is in another circuit 254 across the transformer secondary 232 which also includes a normally open switch 255 of the mat relay 231 normally closed switch 256 of the safety relay 239 and normally closed switch 258 of the time delay relay 253. A normally open holding switch 260 of the holding relay 251 is connected in parallel across switches 255 and 256 to deliver current to the solenoid 250 regardless of the condition of switches 255 and 256. The holding relay 251 includes switch 220 of the motor circuit 221.

The solenoid 262 of a servo actuating relay 263 is in another circuit 264 across the secondary 232 and also includes a normally open switch 266 of the holding relay 251.

Finally, a rectifier 268 in a circuit 270 is connected across the secondary 232 to deliver D.C. to the servo system 272.

The servo motor 162 in the servo system is one which changes direction of rotation with a change of polarity of its terminals 274 and 276.

Solenoid 262 is connected to operate a gang of three, singlepole, double-throw switches 278, 280 and 282. Switch 278 is connected by lead 284 to the pole 274 of the servo motor. Switches 280 and 282 are connected together by lead 286. The positive terminal 288 of the rectifier is connected by a lead 290 to a separated pair of contacts 292 and 294. The negative terminal 296 of the rectifier is connected by a lead 298 to a pair of contacts 300 and 302 opposite the contacts 292 and 294. Contacts 292 and 302 constitute the alternate terminals for switch 278 and contacts 294 and 300 constitute the alternate terminals for switch 280. Thus, when solenoid 262 is de-energized as shown, lead 286 is positively charged and 284 is negatively charged, but upon activation of the solenoid 262, these polarities are reversed. Switch 282 coacts with terminals 304 and 306 to charge respectively lead 308 positively or lead 310 negatively.

The switch at the other end of the leads 308 and 310 comprising the contacts 312 and 314 and the blade 316 connected to the other terminal 276 of the servo motor is the switch 198 discussed above in conjunction with FIGS. 4 and 5; the micro switch which is operated by the movement of nut 174 and screw 168.

The device as thus far described operates as follows. A customer approaches the store door and steps on the mat switch 228, energizingrelay 231. Thereupon switch 244 of delay circuit 242 opens and prevents energization of the time delay relay 253. Relay 231 also closes switch 255 in holding circuit 254 thereby energizing the holding relay 251 which in turn closes the circuit to the holding switch 260 of the holding relay to assure continued energization of the holding relay 251 regardless of the condition of the mat switches 228 and 236. Holding relay also closes switch 225 to start the motor 34 and closes switch 266 to energize the servo relay 263. Energization of the servo relay 263 throws switches 278, 280 and 282, to deliver positive voltage through switch 278 and lead 284 to the motor terminal 274. Since switch 198 has previously been moved to make contact with terminal 314, negative voltage is delivered to the terminal 276 through terminal 300, switch 280, switch 282, and lead 310 and the motor is energized.

Upon energization, the screw 168 will be rotated to advance the nut 174 to its uppermost position, at which point it will strike the upper leg 186 (FIG. 5) of the switch actuator 184, and the lug 196 will move to engage the switch finger 200 of switch 198 thereby moving the blade 316 of the switch out of contact with contact 314 and into contact with contact 312. The circuit to the servo motor is thus broken and the motor will be de-energized.

The advancement of the nut also will move the post 176 upward in the slot 178, and with the movement of the post, the

arm 142 of the servo yoke will be rocked upward, thus rotating the servo yoke counterclockwise as seen in FIG. 4.

At the time the start of the door movement is signalled by the closing of the mat switch 228, the cam follower roller 138 is hearing against cam 38 at the position marked 320. This is the position of the roller yoke at which the rollers 96 have a zero pitch relationship with the shaft 26, or in other words reflect a fully closed condition. From FIG. 16 it will be ap preciated that the roller yoke is free to move counterclockwise off the cam to the cam follower roller position marked 322. This position is represented in full lines in FIG. 7. Since there is no constraint on the roller yoke 124 the pressure of the rotated spring on the lugs 128 will cause the roller yoke to move the position of FIG. 7 and so impart a helical engagement of the rollers 96 on the shaft 26 and cause the door to open.

Opening movement of the door will continue uniformly until the cam follower roller 138 first encounters the cam 36 at the point marked 324. As movement of the door thereafter continues, the cam follower roller will be arcuately urged continuously to its vertical position as illustrated in FIG. 8. The servo yoke will maintain its position determined by the servo assembly, and the return of the roller yoke, therefore, will be against the force of the spring 148, the lower lug 128 backing deeply into the groove extension 146 and the upper lug'128 moving out of the upper groove extension and compressing the spring against the lower spring shoulder 147.

It will be appreciated that as the roller yoke 124 is progressively restored to the vertical, the helical pitch of the rollers 96 on the shaft 26 will be progressively reduced until the rollers are directly transverse thereto and occupy a relationship of zero pitch. This point will occur at the cam follower position marked 326. At this point, of course, the door opening movement will stop. In the course of such movement, however, between the points 324 and 326, the motion of the door will progressively diminish and thus provide a very gentle end to the opening movement.

This progressive slowing of the movement of the door as it approaches the end of its travel is, of course, of greater consequence in the closing movement of the door rather than the opening movement. From the nature of the cams 36 and 38, it will be appreciated that the cam and roller 138 relation functions in precisely the same manner at closing as at opening. However, it is consequential in the opening movement as well in that the velocity of opening may be relatively high (as controlled by the speed control screws 136) and thus a progressive slowing would avoid inertial shocks.

Reverting to the circuit diagram, as the person steps into the doorway off the entering mat and onto the safety mat 236, relay 231 will be restored and safety relay 239 energized. With normally closed switches 244 and 246 associated respectively with the two mat relays 231 and 239, it will be appreciated that an open circuit will continue to exist to the time delay relay 253, thus putting off the time of its initiation. Also, the direct circuit to the winding 250 of the holding relay 251 will be opened by virtue of the restoration of switch 255 or the energization of switch 256.

When both mats are unloaded as by the traffic having cleared the door, switches 244 and 246 in the time delay circuit 242 will close and the time delay relay 253 will be energized through the now closed switch 248 held by the holding switch 260 in the holding circuit. After the desired time interval has elapsed, the switching element of the relay 253 will be actuated first to open switch 258 in the holding circuit 254 and thus de-energize the holding relay 251. Upon this occurrence, switch 248 in the time delay circuit 242 will open thus terminating the heating of the thermal relay 253. Switch 220 in the motor circuit will open to de-energize the motor 34. Switch 260 will open to open the holding circuit of the holding relay 251. Switch 266 in the servo relay circuit 264 will open to de-energize the servo relay 263 and cause a restoration of the switch blades 278, 280 and 282 to their illustrated position. Likewise, the motor will be re-energized through now closed switch 225 in circuit 223. The final effect, therefore, is that the motor 34 continues to operate, but the switches associated with the servo relay 263 have been moved to their altemate position.

Upon such movement of the switch blades, negative voltage will be imposed on the servo motor terminal 274 through lead 292, switch blade 278, and lead 284. Positive voltage will be imposed on terminal 276 through switch blade 314 now in contact with contact 312, lead 308, contact 304, switch blade 282, lead 286, switch blade 280, contact 294 and lead 290 from the positive terminal 288 of the rectifier 268. Thus reverse rotation will be imposed on the servo motor, and the threaded shaft 168 will turn in a direction to move the nut 174 downward as illustrated in FIG. 5. The nut will continue to descend until it actuates the lower leg 186 of the reversing switch actuator 184 at which point switch blade 136 is moved again to contact 314 and the servo motor is de-energized. The post 176 moves downwardly with the nut 174 carrying with it the arm 142 of the servo yoke 126. As the servo yoke thus rotates, the spring 148 will first be unloaded, and through the remaining half of the servo yoke movement, the cam follower roller 138 of the roller yoke 124 is moved away from the cam 36 to the cam follower position indicated at 328. At this point, the rollers 96 will have an opposite helical bearing on the shaft 26 and the door will be moved to closure until it intercepts the cam 38 at the position indicated as 330 where the pitch of the rollers is progressively diminished until they arrive at point 320 where they are normal to the shaft, the door is fully closed, and no further motion is imparted to the door.

During this time of closure, the thermal relay 253 is cooling. The rate of cooling is such that the switch elements will not return to their illustrated unactivated condition until after the time required for the closing movement. At the expiration of such time, the switch elements 258 and 225 revert to the position shown, de-energizing the motor 34 and conditioning the circuitry for another opening cycle.

To summarize the operation, when the door is closed, the servo yoke 126 is held at the upper, counterclockwise extreme of its travel by the nut 174 and the roller yoke is held in its central, neutral position against the spring 148 by the cam 38 as shown in FIG. 8. When the operating cycle is initiated, the nut 174 moves down to rock the servo yoke to its other extreme. The first half of this movement unloads the spring, placing the parts momentarily in the relationship of FIG. 6 and then carries the roller yoke off the cam 38 to the dotted line position of FIG. 7, which, in turn, moves the rollers 96 into their helical relationship for door opening.

The roller yoke tracks the servo yoke until the speed control screw 136 meets the pin 123 of the roller housing, at which point it is stopped, the servo yoke continuing on along to the end of its arc. The spring 148 yields to permit this relative overrun.

At the end of the opening movement, the roller 138 intercepts cam 36 and the roller yoke 124 is restored to its center neutral position against the force of the spring 148.

The closing, which automatically follows, pursues exactly the same sequence. The nut 174 runs to its uppermost position, moving the servo yoke to the other end of the arc. During the last half of this movement, the roller yoke is carried off cam 36 to impart an opposite helical engagement of the rollers on shaft 26. The other speed control screw 136 limits the pitch of the rollers 90. Closing movement continues until the cam follower roller 138 meets cam 38 to restore the system to its starting condition.

Certain modifications or variations are contemplated in the practice of this invention. One such is shown in FIGS. 11 and 12. The purpose served by this modification is the avoidance of a reversing servo motor and associated circuitry. In this modification there is shown a roller housing 82, the roller yoke 124 and the servo yoke 126 operatively connected in essentially the same fashion as described above. In this present modification, the servo motor 162 has a speed reducing gear box 340 associated therewith which, in turn, has an output shaft 342 extending parallel to the shaft 26. A bracket 344 connected to the gear box 340 mounts the servo motor and gearing rigidly to the top of the horizontal web 44 of the trolley 24.

The output shaft 342 of the gear box has an arm 346 extending radially therefrom which mounts a roller 348 at its outer end, the roller being on that side of the arm 346 away from the servo motor and facing the servo yoke 126. The servo yoke again has an operating arm 350 extending radially outward therefrom confronting the roller 348. To the face of this arm 350 is secured a crosshead 352 configured to have a central horizontal groove 354 defined by top and bottom rails 356 and 358. The vertical height of the groove is such as to accommodate closely the roller 348.

The servo will be actuated here to rotate the arm 346 to its vertically upward position upon actuation of the door opening switch at which point the servo motor will stop. This will impart the same movement to the servo yoke as the movement of the nut 174 in the first described embodiment in its uppermost position. Upon the call for door closure, the arm will rotate to its vertically downward position and then stop. The engagement of the roller with the wall 358 of the crosshead 352 will carry the servo yoke downward in a fashion equivalent to the movement of the nut 174 to the lower end of the shaft 168 and so orient the rollers helically 96 for door closing movement. The roller yoke 124 with its associated cam follower roller 138 will be alternatively controlled by the servo yoke and the cams 36 and 38 in precisely the fashion as described before.

The structure illustrated in FIGS. 13 through 15 shows yet another mechanism for achieving the necessary movement of the servo yoke. The purpose to be achieved here is the stationary placement of the servo motor 162. To this end, the servo motor will possess a gear case 370 and an output shaft 372 in the same fashion described in connection with the modification of FIGS. 11 and 12. The servo motor and gear case may be mounted by a bracket 374 to the top wall of the support member 12.

The output shaft 372 has a generally horizontal short crank 376 mounted thereto consisting of a radially extending finger 378 and a bearing 380 at its outer end. The servo motor and gear case serve to rotate the crank 376 in 180 increments between its uppermost and lowermost positions. A square shaft 382 spans the range of movement of the trolley 24 and may be supported from the top wall of the support member at each end. As shown in FIG. 13, the left end is supported by the bracket 374 and the right end will be supported by a similar bracket (not shown). The shaft 382 is supported for rotation, each end thereof having a cylindrical extension 384 which is contained within a bearing 386 mounted to the bracket 374 at its left end and to a like bracket (not shown) at its right end. A relatively long rocker arm 388 is secured to the shaft 382 and extends out generally parallel to and aligned with the crank 376. A link 390 connects the free ends of the crank and the rocker arm such that the shaft 382 will be rocked alternately up and down by rotation of the crank 376.

A bracket 392 is secured by a foot 394 to the trolley 24 and is circularly apertured as at 396 to embrace loosely the square shaft 382. The aperture contains a spool-shaped bearing 398 having a central square aperture 400 therein embracing closely the shaft 382. One of the flanges 402 has a gear segment 404 mounted to the face thereof.

A corresponding gear segment 406 is mounted to the exposed back face 408 of the servo yoke 126 in mesh with the gear segment 404 by screws 410 or the like.

In this modification, rotation of the crank 376 alternately to its upward position and downward position will rock the shaft 382 through, for instance, a 90 arc alternately upward and downward through the medium of the link 390 and the rocker arm 388. The bearing 398 is longitudinally slidable along the square shaft 382 and will be carried along the shaft with the door operating mechanism by the bracket 392, the gear sector being held in constant mesh with the gear segment 406 on the servo yoke 126. Rocking of the shaft 382 will, of course, rock the gear sector, so imposing an opposite movement on the servo housing 126.

Yet another structural altnerative is illustrated in FIGS. 18, 19 and 20. Because of the resilient mounting of the actuator assembly together with the somewhat loose fit of it on the shaft 26, it will be appreciated that the bearing of the cam follower roller 138 on its associated cam at the end of the travel of the door in either direction will tend to cock the assembly on the shaft. It will also be appreciated from the foregoing description of the wiring diagram that the motor 34 is called on to start at a time when the cam follower roller is bearing against the cam with full force. This cocking of the actuator assembly 52 will cause it to bind on the shaft, imposing a starting load on the motor and causing it to come up to speed slowly and to heat up. In FIGS. 18, 19 and 20 an optional servo yoke is disclosed which carries the cam follower roller 138 and which is mounted rigidly to the trolley entirely independently of the roller housing so as to avoid such torsional thrusts on the actuator assembly or roller housing.

This assembly 448 includes first a servo yoke support bracket 450, a metal plate having a large hole 452 therein to encompass shaft 26. A bent-over foot 454 is secured to the horizontal web 44 of the trolley 24. Another bent-over car 456 is secured to the vertical web 40 of the trolley. A third, speed control tab 458 is formed to the front of the bracket by bending through a right angle on a horizontal line radial to the hole 452. The tab 458 has a pair of radially spaced tapped holes thereon for the reception of a pair of speed control studs 460. A sleeve 462 is welded to the bracket about the hole 452 and is grooved at its free end for a retainer ring 464.

A second metal plate element, a cam follower 466, is rotatably mounted on the sleeve 462 next to the bracket 450, the cam follower having a large central hole 468 for such purpose. At its top, the follower has a bent-over ear 470 with a tapped hole therein for the reception of the shaft 472 of the cam follower roller 138. Under the ear 470 the cam follower has a pair of pins 474, approximately on a vertical line on opposite sides of the hole 468 extending horizontally therefrom. The pins 474 serve the same function as the lugs 128 of the principal described form. A roller yoke pin 476 extends oppositely from the follower directly below the car 470. A pair of teeth 478 and 480 extend out to the front of the follower having generally parallel, roughly radial, facing edges 482 and 484. Tooth 478 is longer than tooth 480 and has an offset 486 in its central portion as best seen in FIG. 20. The facing edges of the teeth 478 and 480 are in the plane of the speed control studs to coact therewith. The offset 486 in the tooth 478 permits access to the inner stud 460 for adjustment thereof (FIG. 20).

The roller yoke pin spans the separation between the servo yoke assembly 448 and the roller housing 82. The roller housing in this embodiment is essentially the same as that described before, including the sleeve 120. In this case, however, the sleeve has mounted on it only a roller yoke 488. The roller yoke 488 is similar to the yoke 124 in that it is molded and possesses wrist pin pockets 132. Otherwise, it is notably simpler, possessing as its only other operative characteristic a peaked top 490 having a slot 492 therein closely receiving the free end of the roller yoke pin 476.

A molded servo yoke 494, essentially identical with the first described servo yoke 126, is mounted on the sleeve 462, and completes the assembly. It includes an integral servo arm 496 for operative connection to the servo assembly in any of the ways described above. It also includes the slightly less than semi-circular slot 498 with continuing end extensions 500 of less width. The slot 498 contains a coil spring 502, and the pins 474 of the cam follower, the pins moving, one to recede into its adjacent slot extension 500 and the other to compress the spring 502.

The operation of this modification will be apparent from its description. At an end point of travel of the door, the servo yoke 494 will be cocked in one direction, but the cam follower will be positioned by the appropriate cam 36 or 38 in the upright, center position, thereby orienting the roller yoke through the medium of roller yoke pin 476 to a zero pitch roller bearing on the shaft 26. This position of the cam follower will be achieved against the force of the servo yoke spring 508. It will be noted, however, that no torsional strains are imposed on the flexibly supported roller housing; all such strains are borne by the servo yoke support bracket which is rigidly supported by the trolley 24 and avoids engagement with the shaft 26. The shaft, thus, is free of any binding.

Certain specific alternatives and design options have been described above. Another conceivable variation might be a slip clutch coupling the roller yoke and the servo yoke. Such a coupling would be yielding in the same functional fashion as the resilient spring-based interconnection taught in that the servo yoke could still travel its predetermined are which the roller yoke would track to the extent it was free, but the speed control screws and the cam-roller interaction would override the tracking relationship.

Such specific inclusions are not to be regarded as exhausting the alternatives and options possible. Different exigencies may well demand other variations than those taught without departing from the essence of the invention as defined in the claims hereof.

I claim:

1. A sliding door operator comprising a shaft powered for rotation oriented in the direction of door movement, a door, and an operating assembly operatively secured to said door and engaged on said shaft, said assembly including a roller bearing against said shaft to be driven thereby, said roller being mounted by said assembly for rotation about an axis normal to the surface of said shaft to effect a helical engagement of said roller on said shaft of variable pitch, roller controlling means connected to said roller to effect said rotation about said axis, positive means adapted to move said roller controlling means to rotate said roller for door movement yieldably connected to said roller controlling means, and means operative on said roller controlling means at the end of door travel to reduce the pitch of said roller engagement against said yieldable connection.

2. The combination of claim 1 wherein said pitch reduction continues to zero.

3. The combination of claim 1 wherein said assembly includes a plurality of said rollers grasping said shaft therebetween, and said roller controlling means is a yoke connected to each of said rollers to move all alike.

4. The combination of claim 1 wherein said positive means is operatively connected to said roller controlling means by a spring.

5. The combination of claim 1 wherein said operative means includes a fixed cam associated with the end of door travel and a follower on said assembly.

6. A sliding door operator comprising a shaft powered for rotation, a door, and an operating assembly operatively secured to said door and engaged on said shaft, said assembly including a roller bearing against said shaft to be driven thereby, said roller being mounted by said assembly for rotation about an axis normal to the surface of said shaft variably to either side of a position where the axes of said shaft and said roller are parallel to effect a helical engagement of said roller on said shaft of continuously variable pitch in either direction, roller controlling means connected to said roller to effect said rotation in either direction, positive means adapted to turn said roller controlling means optionally in either direction, yieldable means interconnecting said positive means and seating roller controlling means, and means operative on said roller controlling means at each end of door travel to turn the axis of said roller to progressively reduce the pitch of said roller engagement against said yieldable means.

7. The combination of claim 6 wherein said pitch reduction continues to zero to stop said door at each end of said travel.

8. The combination of claim 6 wherein said assembly includes a plurality of said rollers grasping said shaft therebetween and said roller controlling means is a yoke connected to each of said rollers to move all alike.

9. The combination of claim 6 wherein said positive means is operatively connected to said roller controlling means by a spring.

10. The combination as set forth in claim 6 including a fixed cam associated with each end of door travel and a cam follower operatively connected to said roller controlling means engageable with said cams to effect said reduction of pitch of roller engagement.

1]. The combination as set forth in claim 6 including additionally adjustable means operatively connected to said roller controlling means to limit said rotation of said roller in each direction against said resilient means.

12. The combination as set forth in claim 6 wherein said positive means comprises an arm mounted for pivotal movement with respect to said shaft, and means for moving said arm through an are.

13. The combination of claim 12 wherein said roller controlling means is rotatable through an are about said shaft for said roller control, and one of said members as between said arm and said roller controlling means has a spring contained concentrically with said shaft and the other of said members has a lug opposing each end of said spring to resiliently resist displacement of said roller controlling means from a predetermined angular relationship with said arm.

14. A sliding door operator comprising a shaft powered for rotation oriented in a direction of door movement, a door, and an operating assembly operatively secured to said door and engaged on said shaft, said assembly including a plurality of rollers grasping said shaft therebetween, each of said rollers being mounted by said assembly for rotation about an axis normal to the surface of said shaft variably to each side of a position where the axes of said shaft and said rollers are parallel to effect a helical engagement of said rollers on said shaft of continuously variable pitch in either direction, a roller yoke rotatable concentrically with said shaft to rotate said rollers all alike about said axes, a servo yoke rotatable concentrically about said shaft, means yieldably connecting said servo yoke and said roller yoke to cause said roller yoke normally to track said servo yoke, a servo mechanism for moving said servo yoke in both directions through a predetermined arc, control means for energizing said servo mechanism to move said servo yoke alternately between the ends of said arc upon energization thereof, and means adjacent the end points of travel of said operating assembly to impose said parallel axis position on said roller yoke against said yieldable connection.

15. A linear actuator comprising a shaft powered for rotation, and an operating assembly engaged on said shaft for relative linear movement therebetween, said assembly including a plurality of rollers grasping said shaft therebetween, each of said rollers being mounted by said assembly for rotation about an axis normal to the surface of said shaft variably away from a position where the axes of said shaft and said rollers are parallel to effect a helical engagement of said rollers on said shaft of continuously variable pitch, a roller yoke rotatable concentrically with said shaft to rotate said rollers alike about said normal axes, and means movable between limits yieldably connected to said roller yoke to cause said roller yoke to track said movable means normally, said roller yoke being movable against the resistance of said yieldable connection in nontracking relationship with said movable means.

16. The combination of claim 15 wherein said rollers are rotatable in either direction away from said paralleled axis position and said yieldable connection permits non-tracking movement of said roller yoke in either direction.

17. The combination of claim 15 wherein said movable means is operatively connected to said roller yoke by a spring.

18. The combination of claim 15 wherein said movable means is arcuately movable about said shaft.

19. The combination of claim 18 wherein one of said members as between said yoke and said movable means has a spring contained concentrically with said shaft and the other of said members has a lug opposing each end of said spring to resiliently resist displacement of said yoke from a predetermined angular relationship with said movable means.

g;;g UNITED STATES P TENT OFFICE CERTIFICATE (IQRRECTION Patent No. 3 670 455 Dated June 20, 1972 Inventor-(s). Loren E. Slaybaugh- It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Col. 5, line 20, "alot" should be --slot--.

Claim 6, line 65, "seating" should be -said--.

Signed and sealed this ZLLth day of October 1972.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. RUBEDT QOT'I'SCHALK Attesting; Officer COmI IlSSlOOGI of Patents 

1. A sliding door operator comprising a shaft powered for rotation oriented in the direction of door movement, a door, and an operating assembly operatively secured to said door and engaged on said shaft, said assembly including a roller bearing against said shaft to be driven thereby, said roller being mounted by said assembly for rotation about an axis normal to the surface of said shaft to effect a helical engagement of said roller on said shaft of variable pitch, roller controlling means connected to said roller to effect said rotation about said axis, positive means adapted to move said roller controlling means to rotate said roller for door movement yieldably connected to said roller controlling means, and means operative on said roller controlling means at the end of door travel to reduce the pitch of said roller engagement against said yieldable connection.
 2. The combination of claim 1 wherein said pitch reduction continues to zero.
 3. The combination of claim 1 wherein said assembly includes a plurality of said rollers grasping said shaft there-between, and said roller controlling means is a yoke connected to each of said rollers to move all alike.
 4. The combination of claim 1 wherein said positive means is operatively connected to said roller controlling means by a spring.
 5. The combination of claim 1 wherein said operative means includes a fixed cam associated with the end of door travel and a follower on said assembly.
 6. A sliding door operator comprising a shaft powered for rotation, a door, and an operating assembly operatively secured to said door and engaged on said shaft, said assembly including a roller bearing against said shaft to be driven thereby, said roller being mounted by said assembly for rotation about an axis normal to the surface of said shaft variably to either side of a position where the axes of said shaft and said roller are parallel to effect a helical engagement of said roller on said shaft of continuously variable pitch in either direction, roller controlling means connected to said roller to effect said rotation in either direction, positive means adapted to turn said roller controlling means optionally in either direction, yieldable means interconnecting said positive means and said roller controlling means, and means operative on said roller controlling means at each end of door travel to turn the axis of said roller to progressively reduce the pitch of said roller engagement against said yieldable means.
 7. The combination of claim 6 wherein said pitch reduction continues to zero to stop said door at each end of said travel.
 8. The combination of claim 6 wherein said assembly includes a plurality of said rollers grasping said shaft therebetween and said roller controlling means is a yoke connected to each of said rollers to move all alike.
 9. The combination of claim 6 wherein said positive means is operatively connected to said roller controlling means by a spring.
 10. The combination as set forth in claim 6 including a fixed cam associated with each end of door travel and a cam follower operatively connected to said roller controlling means engageable with said cams to effect said reduction of pitch of roller engagement.
 11. The combination as set forth in claim 6 including additionally adjustable means operatively connected to said roller controlling means to limit said rotation of said roller in each direction against said resilient means.
 12. The combination as set forth in claim 6 wherein said positive means comprises an arm mounted for pivotal movement with respect to said shaft, and means for moving said arm through an arc.
 13. The combination of claim 12 wherein said roller controlling means is rotatable througH an arc about said shaft for said roller control, and one of said members as between said arm and said roller controlling means has a spring contained concentrically with said shaft and the other of said members has a lug opposing each end of said spring to resiliently resist displacement of said roller controlling means from a predetermined angular relationship with said arm.
 14. A sliding door operator comprising a shaft powered for rotation oriented in a direction of door movement, a door, and an operating assembly operatively secured to said door and engaged on said shaft, said assembly including a plurality of rollers grasping said shaft therebetween, each of said rollers being mounted by said assembly for rotation about an axis normal to the surface of said shaft variably to each side of a position where the axes of said shaft and said rollers are parallel to effect a helical engagement of said rollers on said shaft of continuously variable pitch in either direction, a roller yoke rotatable concentrically with said shaft to rotate said rollers all alike about said axes, a servo yoke rotatable concentrically about said shaft, means yieldably connecting said servo yoke and said roller yoke to cause said roller yoke normally to track said servo yoke, a servo mechanism for moving said servo yoke in both directions through a predetermined arc, control means for energizing said servo mechanism to move said servo yoke alternately between the ends of said arc upon energization thereof, and means adjacent the end points of travel of said operating assembly to impose said parallel axis position on said roller yoke against said yieldable connection.
 15. A linear actuator comprising a shaft powered for rotation, and an operating assembly engaged on said shaft for relative linear movement therebetween, said assembly including a plurality of rollers grasping said shaft therebetween, each of said rollers being mounted by said assembly for rotation about an axis normal to the surface of said shaft variably away from a position where the axes of said shaft and said rollers are parallel to effect a helical engagement of said rollers on said shaft of continuously variable pitch, a roller yoke rotatable concentrically with said shaft to rotate said rollers alike about said normal axes, and means movable between limits yieldably connected to said roller yoke to cause said roller yoke to track said movable means normally, said roller yoke being movable against the resistance of said yieldable connection in non-tracking relationship with said movable means.
 16. The combination of claim 15 wherein said rollers are rotatable in either direction away from said paralleled axis position and said yieldable connection permits non-tracking movement of said roller yoke in either direction.
 17. The combination of claim 15 wherein said movable means is operatively connected to said roller yoke by a spring.
 18. The combination of claim 15 wherein said movable means is arcuately movable about said shaft.
 19. The combination of claim 18 wherein one of said members as between said yoke and said movable means has a spring contained concentrically with said shaft and the other of said members has a lug opposing each end of said spring to resiliently resist displacement of said yoke from a predetermined angular relationship with said movable means. 